Taxable Income For Employee Of A Foreign Country In The US

I work for a foreign consulate in the USA. I do not receive a W2 and no taxes are withheld and no income is reported. In addition to my monthly base pay, the consulate includes a monthly payment equal to one half of the normal FICA taxes. When I file my taxes I pay self employment taxes as if I were an independent contractor. For my taxable income I have been claiming both my normal monthly base pay plus the monthly payment equal to one half of the FICA taxes. 
 
Should my taxable income be considered only my base monthly pay, or should I also include the monthly 1/2 FICA payment from my employer? Maybe I am overstating my taxable income?